Technical Abstract:
Switchgrass has great potential as a sustainable bioenergy crop. However, prior reports suggest insect damage can interfere with switchgrass establishment and yield. The fall armyworm is a pest of many different grass crops (including maize and rice) and is thus potentially an important pest of switchgrass once it moves into widespread cultivation. Significant differences in fall armyworm damage were noted for six commercially available cultivars examined, which were influenced by plant age and fertility. Some native switchgrass plants were highly resistant and caused high levels of mortality after only two days. Lines selected from a cross of high- and low-lignin parents showed significant differences in resistance compared to both parents in some cases. Some low-lignin lines had fall armyworm resistance that was similar to high-lignin lines. In the commercial cultivars, sequence differences were noted for four insect/disease resistance genes that were homologs of those from corn. Switchgrass RNA hybridized well to commercially available maize arrays. Further identification of insect resistance genes can lead to more effective development of sustainable switchgrass lines. These insect resistance genes may also have value as sources of insect resistance for other crops such as corn, thereby indirectly reducing ear mold toxins and providing safer food for humans and animals.